A Mexican court determined which evidence is sufficient to prove a disputed charge, pertaining to online purchases, especially because banks have the burden of proof to demonstrate that the purchase was made.


In a commercial trial, the plaintiff demanded from a defendant (a bank), the nullity of several transactions realized online. On the other hand, the bank offered as evidence to prove the plaintiff’s authorization of such transactions the so-called “transaction logging” [1], as well as an expert computing opinion. The judge declared the nullity of the transactions realized, since there were no grounds to conclude that the plaintiff had authorized such charges. The above based on the evidence offered by the defendant.

Federal court’s rationale

The Third Collegiate Tribunal in Civil Matters (the “Court”) determined that online purchases, the one-time code [2] entered by the user, and which registry is at the transaction logging, and which is explained by an expert computing opinion, is sufficient to prove the authorization of a challenged charged. [3]

The Court justified its decision on the grounds hat the banking transactions, the electronic signature is a valid source of obligations for the cardholders linked to such security means.

However, it also concluded that the bank shall prove that the user is the one who performed such transactions. This happens when the bank proves that it verified the user identity trough the verifying methods used in transactions prior agreed with the user.


According to the Court, the use of the one-time code is equivalent to the electronic signature. Therefore, online charges shall be regarded as authorized by the user when the bank proves that it verified his/her identity to validate the purchase, through such code.

By Monserrath Bustamante

[1] Database where all the changes on the data are registered. The use of logging areas has as its foundation a transactional concept.

[2] Code or password with digit chain that is created and sent to a user to be used with a sole intent to log in.

[3] https://sjf2.scjn.gob.mx/detalle/tesis/2026259

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